For many two-stroke motorcycle enthusiasts, especially fans of the legendary Yamaha RD series, the “escapamento RD” (Portuguese for RD exhaust) is far more than just a replacement part or a cosmetic upgrade. It’s a vital component that defines performance, sound, and even the very character of the machine. The right exhaust can dramatically transform how the bike responds, how it sounds, and even how efficiently it consumes fuel.
In this article, we’ll take a deep dive into Yamaha RD exhausts: their history, structure, aftermarket vs OEM differences, benefits and trade-offs, maintenance tips, examples of products on the market, and how to choose the perfect setup for your bike.
Origins of the Yamaha RD Series
The Yamaha RD series — short for Race Developed — appeared in the 1970s and quickly gained cult status. Compact, lightweight, and featuring high-revving two-stroke engines, models like the RD125, RD250, RD350, and RD400 made history. The stock exhausts fitted by Yamaha balanced power delivery with reliability and everyday usability, while still offering that unique RD two-stroke sound.
Over time, aftermarket companies and small workshops began producing performance exhausts, tuned expansion chambers, replicas, and custom builds. Riders sought more horsepower, sharper throttle response, or simply the aggressive, raspy tone that made these bikes unforgettable.
How a Two-Stroke Exhaust Works
To appreciate RD exhausts, you need to understand the basics of two-stroke engine dynamics:
-
Exhaust and intake ports: In two-stroke engines, the piston uncovers both intake and exhaust ports at different times. Poorly designed exhausts can allow fresh fuel-air mix to escape with burnt gases.
-
Pressure waves & resonance: Expansion chambers use pressure waves bouncing inside the exhaust to push unburned mixture back into the cylinder before the port closes, improving efficiency and power.
-
Power band: Exhaust geometry dictates where power is delivered. Shorter chambers usually boost high-RPM performance, while longer chambers can improve torque in the mid-range.
-
Noise control: A freer exhaust often means more noise. While exhilarating for riders, regulations in many countries set strict noise and emissions standards.
Anatomy of an RD Exhaust
An RD exhaust is made up of several critical sections:
| Component | Function |
|---|---|
| Header pipe | Connects the cylinder exhaust port to the expansion chamber; diameter affects flow. |
| Diffuser cone | Expands gas flow; shape and angle control speed and pressure drop. |
| Belly (chamber body) | The largest part of the expansion chamber, central to pressure wave tuning. |
| Reflector cone | Narrows back down, sending pressure waves back toward the cylinder. |
| Silencer / end-can | Reduces noise; often uses packing material or baffles. |
Common materials
-
Mild steel: Affordable, easy to weld, but prone to corrosion.
-
Stainless steel (304/316): Durable, corrosion-resistant, keeps appearance under heat.
-
Chrome-plated steel: Classic look but plating may discolor or peel under heat.
-
Aluminum: Often used for silencers/end-caps; light but less heat-resistant.
-
Carbon fiber / titanium: High-end aftermarket options; lightweight and stylish but expensive.
OEM vs Aftermarket RD Exhausts
| Aspect | OEM (Original) | Aftermarket |
|---|---|---|
| Fitment | Perfect fit, vibration tested, designed by Yamaha. | May need adjustments (brackets, springs, flanges). |
| Performance | Balanced for reliability and everyday riding. | Can unlock extra horsepower, especially at higher RPMs. |
| Weight | Heavier, durable materials. | Often lighter, thanks to thinner walls or exotic alloys. |
| Sound | Controlled, compliant with laws. | Louder, more aggressive, sometimes too loud for street use. |
| Durability | Long-lasting, though aging OEMs are rare. | Quality varies; high-end stainless systems last decades, cheap replicas may not. |
| Cost | Expensive, especially rare OEM parts. | Wide range: from budget replicas to premium tuned chambers. |
Price Ranges & Popular RD Exhaust Options
Based on current markets in Brazil and abroad:
-
Dogster Escapamentos (Brazil): Handmade stainless exhausts for RD125/135 and RD350, tuned for performance. Prices from about R$1,390 – R$2,480 (US$280–500).
-
DG Performance (USA): Classic DG exhausts for RD400, reducing weight and boosting horsepower. Around US$700–1,000.
-
JL (Jim Lomas): Premium expansion chambers for RD250/350, available in stainless or mild steel with carbon silencers. US$800–1,400+.
-
Second-hand market (OLX, MercadoLivre, eBay): Used or replica RD135/RD350 exhausts from R$600–1,500 depending on condition and originality. Rare OEMs fetch higher prices.
Choosing the Right Exhaust for Your RD
When shopping for an RD exhaust, consider:
-
Bike model: RD125, RD135, RD350, RD400, and whether it’s air-cooled or liquid-cooled.
-
Riding style: Daily commuting, racing, restoration, or weekend rides?
-
Material & weight: Stainless for durability, mild steel for affordability, exotic alloys for performance.
-
Chamber geometry: Short vs long expansion chambers influence torque vs top-end power.
-
Installation & tuning: New exhausts may require carb jetting adjustments or ignition tweaks.
-
Legal compliance: Street-legal noise/emission rules may limit your options.
-
Looks: Chrome, brushed steel, or carbon fiber finishes add personality.
Maintenance & Care
Two-stroke exhausts require more attention than four-stroke systems:
-
Carbon deposits: Oil-rich mixtures cause soot buildup; clean periodically to restore flow.
-
Rust & corrosion: Especially in mild steel; stainless is far more resistant.
-
Packing replacement: Silencers need repacking for proper sound and backpressure.
-
Leaks: Check gaskets, flanges, and springs for tight seals.
-
Re-tuning: Carb adjustments may be required after exhaust changes to avoid overheating or lean running.
Restoration vs Performance
For collectors and restorers, originality is everything: OEM exhausts or high-fidelity replicas preserve value. For performance riders, aftermarket tuned chambers offer sharper throttle response, better top-end power, and reduced weight — at the cost of noise and sometimes mid-range torque.
Case Studies
Scenario A: RD135 commuter + drag racing
A rider wants everyday reliability with weekend bursts on the drag strip. A Dogster stainless exhaust with tuned expansion chamber provides the right mix of durability and performance, though it requires carb jetting.
Scenario B: RD350 restoration project
For collectors, an OEM or OEM-style chrome replica maintains authenticity. While performance gains are secondary, originality preserves resale and historical value.
Cultural Value of RD Exhausts
The Yamaha RD exhaust note is part of motorcycle culture. The raspy growl of an RD135 or the fierce scream of an RD350 at full throttle is instantly recognizable. At vintage bike meets and collector shows, exhaust choice sparks debates about originality, tuning quality, and aesthetics.
Conclusion
The escapamento RD is not just a pipe — it’s a piece of engineering that can transform performance, sound, and even the value of a Yamaha RD. Whether you’re after authenticity for a restoration or chasing every bit of horsepower with a tuned chamber, the right choice depends on your bike model, riding style, and goals.
From OEM classics to modern stainless performance systems, the RD exhaust world offers something for collectors, racers, and everyday enthusiasts alike.
Thanks for reading — and for more in-depth motorcycle guides and reviews, check out News Zio.
